Rastra is an insulated concrete form (ICF for short) that is made from recycled post-consumer polystyrene (aka foam) waste products. Rastra is the trademark name for the actual material, which is called Thastyron. Amazing. It is used for both interior and exterior construction much the same way concrete blocks are including lintels, retaining walls, and load-bearing walls. The forms are filled with concrete for extra structural stability.

Concrete block as you may or may not know is a common building material throughout the world, particularly outside the United States. Besides being easy to install, it is soundproof, fire, frost, and heat resistant. Homes built with Rastra have comparable R-values to homes built using other building methods as well.

The pre-fabricated panels are lightweight yet strong and the material is easily cut, sculpted, or drilled using conventional tools. Another advantage is that the builder can apply plaster directly to interior walls and stucco to exterior walls, saving time and materials.

Although Rastra and other ICF building materials are slightly more expensive and perhaps not for everyone, if you're looking for an environmentally friendly building material that allows ample design creativity, Rastra is probably a good choice. And, if you're a builder who got your start constructing elaborate Lego buildings, you're going to love working with Rastra!